Valve device

ABSTRACT

A valve device includes a housing, a stationary disk, a drive device, a shaft and a rotor. The stationary disk is fixed at an inside of the housing and has at least one flow passage hole. The shaft is rotated about a central axis by the drive device. The rotor increases or decreases an opening degree of the at least one flow passage hole. The rotor includes: a drive disk that slides relative to the stationary disk; and a lever that is fixed to the drive disk and couples between the drive disk and the shaft. A first torsion spring is placed between the housing and the shaft and urges the shaft relative to the housing in a circumferential direction around the central axis, and a second torsion spring is placed between the shaft and the lever and urges the lever relative to the shaft in the circumferential direction.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of International PatentApplication No. PCT/JP2021/033317 filed on Sep. 10, 2021, whichdesignated the U.S. and claims the benefit of priority from JapanesePatent Application No. 2020-163935 filed on Sep. 29, 2020. The entiredisclosures of all of the above applications are incorporated herein byreference.

TECHNICAL FIELD

The present disclosure relates to a valve device.

BACKGROUND

A flow rate control valve is an example of a valve device. For example,one previously proposed flow rate control valve includes: a valveelement; a drive device which drives the valve element; a speed reducerwhich is placed between the valve element and the drive device andincreases a drive torque outputted from the drive device; and a returnspring which urges the valve element that is driven through the speedreducer. The valve element of this flow rate control valve includes adisk (serving as a rotor) and a shaft. The disk and the shaft areconfigured to rotate integrally in a state where the disk isdisplaceable in an axial direction of the shaft.

In the flow rate control valve described above, when the disk, which isthe rotor, is rotated by the drive device, an opening degree of a flowpassage hole, through which the fluid flows from an inlet to an outletof a housing, is increased or decreased.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

According to the present disclosure, there is provided a valve devicethat includes a housing, a stationary disk, a drive device, a shaft anda rotor. The housing forms a fluid passage to conduct fluid at an insideof the housing. The stationary disk is fixed at the inside of thehousing and has at least one flow passage hole. The drive device isconfigured to output a rotational force. The shaft is configured to berotated about a central axis by the rotational force. The rotor isconfigured to increase or decrease an opening degree of the at least oneflow passage hole in response to rotation of the shaft. The rotorincludes a drive disk and a lever. The drive disk is configured to sliderelative to the stationary disk. The lever is fixed to the drive diskand couples between the drive disk and the shaft to enable integralrotation of the drive disk and the shaft. A first torsion spring isplaced between the housing and the shaft and is configured to urge theshaft relative to the housing in a circumferential direction around thecentral axis of the shaft. A second torsion spring is placed between theshaft and the lever and is configured to urge the lever relative to theshaft in the circumferential direction.

BRIEF DESCRIPTION OF DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is a front view of a valve device according to an embodiment.

FIG. 2 is a bottom view of the valve device viewed in a direction of anarrow II in FIG. 1 .

FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1 .

FIG. 4 is a bottom view of a stationary disk on which a gasket isplaced.

FIG. 5 is a cross-sectional view showing a cross-sectional shape of thegasket.

FIG. 6 is a plan view of an assembly of a shaft, a rotor and a lever.

FIG. 7 is a side view of the assembly of the shaft, the rotor and thelever viewed in a direction of an arrow VII in FIG. 6 .

FIG. 8 is a side view of the assembly of the shaft, the rotor and thelever viewed in a direction of an arrow VIII in FIG. 6 .

FIG. 9 is a side view of the assembly of the shaft, the rotor and thelever viewed in a direction of an arrow IX in FIG. 6 .

FIG. 10 is a cross-sectional view taken along line X-X in FIG. 6 .

FIG. 11 is a plan view of the rotor.

FIG. 12 is a side view of the rotor viewed in a direction of an arrowXII in FIG. 11 .

FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG. 12.

FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. 11 .

FIG. 15 is a plan view of the drive disk.

FIG. 16 is a cross-sectional view taken along a line XVI-XVI in FIG. 15.

FIG. 17 is a plan view showing a state where the drive disk is placed onthe stationary disk.

FIG. 18 is a side view showing a state where the drive disk is placed onthe stationary disk.

FIG. 19 is a plan view of the lever.

FIG. 20 is a side view of the lever viewed in a direction of an arrow XXin FIG. 19 .

FIG. 21 is a side view of the lever viewed in a direction of an arrowXXI in FIG. 19 .

FIG. 22 is a bottom view of the lever.

FIG. 23 is a side view of an assembly in which the shaft is assembled toa main body cover.

FIG. 24 is a bottom view of the assembly, in which the shaft isassembled to the main body cover, viewed in a direction of an arrow XXIVin FIG. 23 .

FIG. 25 is a cross-sectional view taken along line XXV-XXV in FIG. 24 .

FIG. 26 is an explanatory diagram for explaining a reference position,an urging range and a non-urging range of a first torsion spring.

DETAILED DESCRIPTION

A flow rate control valve is an example of a valve device. For example,one previously proposed flow rate control valve includes: a valveelement; a drive device which drives the valve element; a speed reducerwhich is placed between the valve element and the drive device andincreases a drive torque outputted from the drive device; and a returnspring which urges the valve element that is driven through the speedreducer. The valve element of this flow rate control valve includes adisk (serving as a rotor) and a shaft. The disk and the shaft areconfigured to rotate integrally in a state where the disk isdisplaceable in an axial direction of the shaft.

In the flow rate control valve described above, when the disk, which isthe rotor, is rotated by the drive device, an opening degree of a flowpassage hole, through which the fluid flows from an inlet to an outletof a housing, is increased or decreased.

However, in the flow rate control valve described above, nocountermeasures are taken to limit rattling in the circumferentialdirection between the disk (serving as the rotor) and the shaft, so thatvariations occur in the opening degree of the flow passage hole. Thevariations in the opening degree of the flow passage hole will causevariations in the flow rate of the fluid, which flows through the valvedevice, so that the variations in the opening degree of the flow passagehole are not desirable. The above finding is made thorough the diligentstudy of the inventor of the present application.

According to one aspect of the present disclosure, there is provided avalve device including:

a housing that forms a fluid passage at an inside of the housing,wherein the fluid passage is configured to conduct fluid through thehousing;

a stationary disk that is shaped in a plate form and is fixed at theinside of the housing, wherein the stationary disk has at least one flowpassage hole which is configured to conduct the fluid through thestationary disk;

a drive device that is configured to output a rotational force;

a shaft that is configured to be rotated about a central axis, which ispredetermined, by the rotational force; and

-   -   a rotor that is configured to increase or decrease an opening        degree of the at least one flow passage hole in response to        rotation of the shaft, wherein:    -   the rotor includes:        -   a drive disk that is shaped in a plate form and is            configured to slide relative to the stationary disk; and        -   a lever that is fixed to the drive disk and couples between            the drive disk and the shaft to enable integral rotation of            the drive disk and the shaft in a state where the drive disk            is displaceable in an axial direction of the shaft;    -   a first torsion spring is placed between the housing and the        shaft and is configured to the shaft relative to the housing in        a circumferential direction around the central axis of the        shaft; and    -   a second torsion spring is placed between the shaft and the        lever and is configured to the lever relative to the shaft in        the circumferential direction.

Therefore, as long as the first torsion spring urges the shaft relativeto the housing in the circumferential direction, the rattling in thecircumferential direction between the drive device and the shaft islimited. In addition, as long as the second torsion spring urges thelever relative to the shaft in the circumferential direction, therattling in the circumferential direction between the shaft and thelever is limited. Since the lever is fixed to the drive disk, the secondtorsion spring limits the rattling in the circumferential directionbetween the shaft and the drive disk.

Therefore, the rattling in the circumferential direction in thetransmission path from the drive device to the rotor can be limited, andthe variations in the opening degrees of the flow passage holes causedby the rattling can be limited.

Hereinafter, an embodiment of the present disclosure will be describedwith reference to FIGS. 1 to 26 . In the present embodiment, there willbe described an example in which a valve device 10 of the presentdisclosure is applied as a control valve installed on a vehicle. Thevalve device 10 shown in FIG. 1 is installed in a fluid circulationcircuit (not shown) in which fluid (coolant in this example) iscirculated through a vehicle drive power source for running the vehicle,a radiator and the like, and the fluid, which is circulated in the fluidcirculation circuit, flows through the valve device 10.

The valve device 10 can increase or decrease a flow rate of the fluid ina flow path that extends through the valve device 10 in the fluidcirculation circuit, and the valve device 10 can also shut off the flowof the fluid in the flow path. For example, LLC, which contains ethyleneglycol, may be used as the fluid. Here, LLC is an abbreviation for LongLife Coolant.

As shown in FIGS. 1 and 2 , the valve device 10 includes a housing 12that forms a fluid passage at an inside of the housing 12 while thefluid passage is configured to conduct fluid through the housing 12. Thevalve device 10 is a three-way valve and is formed such that an inletport 12 a for receiving the fluid, a first outlet port 12 b foroutputting the fluid, and a second outlet port 12 c for outputting thefluid are formed at the housing 12. The valve device 10 functions notonly as a flow path switching valve but also functions as a flow rateadjusting valve that adjusts a flow rate ratio between a flow rate ofthe fluid, which flows from the inlet port 12 a to the first outlet port12 b, and a flow rate of the fluid, which flows from the inlet port 12 ato the second outlet port 12 c.

The valve device 10 is a disk valve that performs a valveopening/closing operation by rotating a valve element shaped in acircular disk form about a central axis CL of a shaft 18 describedlater. In the present embodiment, description of various structures willbe made while assuming that a direction, which is along the central axisCL of the shaft 18 described later, is an axial direction DRa, and aradial direction of the central axis CL, which is perpendicular to theaxial direction DRa, is a radial direction DRr. Also, in the presentembodiment, the description of the various structures will be made whileassuming that a circumferential direction around the central axis CL isa circumferential direction DRc.

As shown in FIG. 3 , in the valve device 10, a stationary disk 14, adrive device 16, the shaft 18, a rotor 20, a compression spring 26, afirst torsion spring 28 and a second torsion spring 30 are received atthe inside of the housing 12. Furthermore, in the valve device 10, thedrive device 16 is placed at an outside of the housing 12.

The housing 12 is a non-rotatable member that does not rotate. Thehousing 12 is made of, for example, a resin material. The housing 12has: a main body 120, which is shaped in a bottomed tubular form andextends in the axial direction DRa; and a main body cover 124 whichcloses an opening 120 a of the main body 120.

The main body 120 has: a bottom wall 121 which forms a bottom surface;and a peripheral wall 122, which circumferentially surrounds the centralaxis CL. The bottom wall 121 and the peripheral wall 122 are formedintegrally in one-piece as an integral molded product.

Two stepped portions (recesses), which correspond to two flow passageholes 141, 142, respectively, of the stationary disk 14 described later,are formed at the bottom wall 121. That is, each of two portions of thebottom wall 121, which are opposed to the flow passage holes 141, 142,respectively, of the stationary disk 14, is further spaced from the mainbody cover 124 than a portion of the bottom wall 121, which is notopposed to the flow passage holes 141, 142 of the stationary disk 14.

The bottom wall 121 has: two opposing portions 121 a, which are opposedto the flow passage holes 141, 142, respectively, of the stationary disk14; and a non-opposing portion 121 b, which is not opposed to each ofthe flow passage holes 141, 142 of the stationary disk 14. The opposingportions 121 a of the bottom wall 121 are largely spaced from thestationary disk 14, and the non-opposing portion 121 b of the bottomwall 121 is adjacent to the stationary disk 14.

The peripheral wall 122 has the inlet port 12 a at a location that iscloser to the opening 120 a than to the bottom wall 121. The peripheralwall 122 also has the first outlet port 12 b and the second outlet port12 c at a location that is closer to the bottom wall 121 than to theopening 120 a. Each of the inlet port 12 a, the first outlet port 12 band the second outlet port 12 c is a tubular member that has a flowpassage therein.

A mounting portion 122 a, on which the stationary disk 14 is placed, isformed at the inside of the peripheral wall 122 at a location betweenthe portion of the peripheral wall 122, at which the inlet port 12 a isformed, and the portion of the peripheral wall 122, at which the outletports 12 b, 12 c are formed. The mounting portion 122 a is a portionthat contacts a back surface of the stationary disk 14 which is oppositeto an opening surface 140 of the stationary disk 14. The mountingportion 122 a is formed at the portion of the peripheral wall 122 wherean inner diameter of the peripheral wall 122 changes. Specifically, themounting portion 122 a is a flat portion that extends in the radialdirection DRr. A receiving groove 122 b, which receives a gasket 15described later, is formed at the mounting portion 122 a.

Furthermore, the peripheral wall 122 has a first disk opposing portion122 c, which is opposed to the stationary disk 14 in the radialdirection DRr, and a second disk opposing portion 122 d, which isopposed to the drive disk 22 in the radial direction DRr.

The first disk opposing portion 122 c has a receiving groove (not shown)that receives a rotation stop projection 144 of the stationary disk 14shown in FIG. 4 . The rotation of the stationary disk 14 may be stoppedby, for example, a rotation stop pin instead of the rotation stopprojection 144.

An inner diameter Dh of the first disk opposing portion 122 c is largerthan an outer diameter Dd of a remaining portion of the stationary disk14, which is other than the rotation stop projection 144. Thereby, a gapis formed between the stationary disk 14 and the peripheral wall 122 ina state where the stationary disk 14 is placed on the mounting portion122 a. In other words, the stationary disk 14 is not positioned by theperipheral wall 122.

An inner diameter of the second disk opposing portion 122 d is largerthan the inner diameter of the first disk opposing portion 122 c. Theinner diameter of the second disk opposing portion 122 d is larger thanan outer diameter of the drive disk 22. Thereby, a gap is formed betweenthe drive disk 22 and the peripheral wall 122. That is, the drive disk22 does not contact the peripheral wall 122 and is not positioned by theperipheral wall 122. The outer diameter of the drive disk 22 issubstantially the same as an outer diameter Dd of the stationary disk14.

The inside of the housing 12 is partitioned by the stationary disk 14into an inlet-side space 12 d and an outlet-side space 12 e. Theinlet-side space 12 d is a space that is communicated with the inletport 12 a at the inside of the housing 12. The outlet-side space 12 e isa space that is communicated with the first outlet port 12 b and thesecond outlet port 12 c at the inside of the housing 12.

Although not shown in the drawing, a partition portion is formed at theinside of the main body 120. The partition portion partitions theoutlet-side space 12 e into a first outlet-side space, which iscommunicated with the first flow passage hole 141, and a secondoutlet-side space, which is communicated with the second flow passagehole 142. This partition portion is formed to extend across theoutlet-side space 12 e in the radial direction DRr.

The main body cover 124 is a lid member that covers the opening 120 a ofthe main body 120. The main body cover 124 has a plate portion 124 a, arib portion 124 b and a boss portion 124 c. The plate portion 124 a, therib portion 124 b and the boss portion 124 c are formed integrally inone-piece as an integral molded product.

The plate portion 124 a is a portion that is shaped in a circular ringform which extends in the radial direction DRr. In the main body cover124, the plate portion 124 a forms the inlet-side space 12 d incorporation with the peripheral wall 122 and the stationary disk 14.

The rib portion 124 b is a portion of the main body cover 124 that isfitted into the opening 120 a of the main body 120. The rib portion 124b is shaped in a tubular form and is placed on a radially outer side ofthe plate portion 124 a. The rib portion 124 b is formed to project fromthe plate portion 124 a toward the bottom wall 121. An O-ring 124 d,which seals a gap between the main body 120 and the main body cover 124,is placed between the rib portion 124 b and the peripheral wall 122.

The boss portion 124 c is a portion through which the shaft 18 isinserted. The boss portion 124 c is shaped in a tubular form and isplaced on a radially inner side of the plate portion 124 a. The bossportion 124 c is provided with: a shaft seal 124 e, which is placed atthe inside of the boss portion 124 c; and an O-ring 124 f, which isplaced at the outside of the boss portion 124 c. The shaft seal 124 e isshaped in a circular ring form and seals between the shaft 18 and theboss portion 124 c, and the O-ring 124 f seals a gap between the bossportion 124 c and the drive device 16. Furthermore, a bearing 124 g,which rotatably supports the shaft 18, is placed at the inside of theboss portion 12 4 c.

The stationary disk 14 is a circular disk member while a thicknessdirection of the stationary disk 14 coincides with the axial directionDRa. The stationary disk 14 has the opening surface 140 as a frontsurface of the stationary disk 14 along which the drive disk 22described later slides. The opening surface 140 is a contact surfacethat contacts a sliding surface 220 of the drive disk 22 which will bedescribed later.

It is desirable that the stationary disk 14 is made of a material thathas a smaller linear expansion coefficient and superior wear resistancethan the material of the housing 12. The material of the stationary disk14 is a high-hardness material that is harder than the material of thehousing 12. Specifically, the stationary disk 14 is made of ceramic.Alternatively, the stationary disk 14 may be formed such that only aportion of the stationary disk 14, which forms the opening surface 140,is made of the material, such as the ceramic, which has the smallerlinear expansion coefficient and the superior wear resistance than thematerial of the housing 12.

In addition, the stationary disk 14 serves as a flow passage formingportion that has the flow passage holes 141, 142 through each of whichthe fluid passes. Therefore, in the valve device 10 of the presentembodiment, the stationary disk 14, which serves as the flow passageforming portion, is formed as a separate member that is formedseparately from the housing 12.

As shown in FIG. 4 , the stationary disk 14 has the first flow passagehole 141 and the second flow passage hole 142 through each of which thefluid passes. The first flow passage hole 141 and the second flowpassage hole 142 are formed in the stationary disk 14 at a location,which is spaced from the central axis CL of the shaft 18, such that thefirst flow passage hole 141 and the second flow passage hole 142 do notoverlap with the central axis CL of the shaft 18. Each of the first flowpassage hole 141 and the second flow passage hole 142 is a through-holethat is shaped in a sector shape (i.e., fan shape), and each of thefirst flow passage hole 141 and the second flow passage hole 142functions as a communication passage that communicates between theinlet-side space 12 d and the outlet-side space 12 e. Here, it should benoted that the first flow passage hole 141 and the second flow passagehole 142 may be formed in any other shape such as a circular shape or anelliptical shape.

Specifically, the first flow passage hole 141 is formed at a portion ofthe stationary disk 14, which corresponds to the first outlet-sidespace, such that the first flow passage hole 141 is communicated withthe first outlet-side space. Furthermore, the second flow passage hole142 is formed at a portion of the stationary disk 14, which correspondsto the second outlet-side space, such that the second flow passage hole142 is communicated with the second outlet-side space.

A stationary disk hole 143, through which the shaft 18 is inserted, isformed generally at the center of the stationary disk 14. The stationarydisk hole 143 has an inner diameter that is larger than a diameter ofthe shaft 18 so as to limit sliding of the shaft 18 along the stationarydisk hole 143.

The gasket 15, which seals a gap between the stationary disk 14 and themounting portion 122 a, is placed between the stationary disk 14 and themounting portion 122 a. The gasket 15 is made of rubber. The gasket 15is received in the receiving groove 122 b which is formed at themounting portion 122 a. As shown in FIG. 5 , two or more projections 151are formed at a seal surface of the gasket 15 which is opposed to thestationary disk 14, and two or more projections 152 are formed atanother seal surface of the gasket 15 which is opposed to the mountingportion 122 a. Specifically, in the gasket 15, two projections 151, 152,which project in the axial direction DRa, are formed at each of the sealsurfaces of the gasket 15. For example, this type of gasket 15 can beobtained by a simple technique such as forming a recess at each of thetwo flat seal surfaces of the gasket.

The drive device 16 shown in FIGS. 1 and 3 is a device for outputting arotational force. Although not shown in the drawing, the drive device 16includes an electric motor and a gear arrangement. The electric motorserves as a drive source, and the gear arrangement serves as a driveforce transmitting member that transmits an output of the electric motorto the shaft 18. For example, a servomotor or a brushless motor is usedas the electric motor in this embodiment. The gear arrangement is formedby a gear mechanism that includes a helical gear or a spur gear.Although not shown in the drawing, the electric motor is rotatedaccording to a control signal outputted from a valve control device thatis electrically connected to the electric motor. The valve controldevice is a computer that includes: a memory, which is a non-transitorytangible storage medium; and a processor. The valve control deviceexecutes a computer program stored in the memory and performs variouscontrol processes according to the computer program.

As shown in FIGS. 3 and 6 , the shaft 18 is a rotatable shaft that isrotated about the central axis CL, which is predetermined, by therotational force transmitted from the drive device 16 through atransmission path. The shaft 18 extends in the axial direction DRa. Twoaxial sides of the shaft 18, which are opposite to each other in theaxial direction DRa, are rotatably supported by the housing 12. That is,the shaft 18 has a double end support structure. The shaft 18 extendsthrough the stationary disk 14 and the drive disk 22 and is rotatablysupported by the housing 12. Specifically, the one axial side of theshaft 18, which is located on one side in the axial direction DRa, isrotatably supported by the bearing 124 g that is placed at the inside ofthe main body cover 124. Furthermore, the other axial side of the shaft18, which is located on the other side in the axial direction DRa, issupported by a bearing hole portion 121 c formed at the bottom wall 121of the main body 120. The bearing hole portion 121 c is formed by asliding bearing. It should be noted that the bearing hole portion 121 cmay be formed by a ball bearing or the like instead of the slidingbearing.

As shown in FIGS. 7, 8, 9 and 10 , the shaft 18 includes a central axisportion 181 and a holder portion 182. The central axis portion 181 ismade of metal, and the holder portion 182 is made of resin and iscoupled to the central axis portion 181. The central axis portion 181and the holder portion 182 are coupled together to integrally rotate.

The central axis portion 181 includes the central axis CL of the shaft18 and extends in the axial direction DRa. The central axis portion 181is a portion that serves as a rotational center of the rotor 20. Thecentral axis portion 181 is formed by a rod member made of metal toensure straightness of the central axis portion 181.

The holder portion 182 is coupled to one axial side of the central axisportion 181 which is located on the one side in the axial direction DRa.The holder portion 182 is shaped in a bottomed tubular form. The centralaxis portion 181 is coupled to a bottom part of the holder portion 182by press fitting or the like. A portion of the holder portion 182, whichprojects to the outside of the housing 12, is coupled to the geararrangement of the drive device 16.

An inner diameter of the holder portion 182 increases stepwise from oneside toward the other side in the axial direction DRa. Specifically, theholder portion 182 includes: an axial coupling portion 183 which islocated at the one axial side in the axial direction DRa; anintermediate portion 184 which is connected to the axial couplingportion 183; a small diameter portion 185 which is connected to theintermediate portion 184; and a large diameter portion 186 which isconnected to the small diameter portion 185. The inner diameter of theholder portion 182 is increased in an order of the axial couplingportion 183, the intermediate portion 184, the small diameter portion185 and the large diameter portion 186.

The axial coupling portion 183 is a portion that is coupled with thecentral axis portion 181. The axial coupling portion 183 has the innerdiameter that is substantially equal to or slightly smaller than anouter diameter of the central axis portion 181. An outside of the axialcoupling portion 183 is supported by the bearing 124 g.

The intermediate portion 184 is a portion which is placed at the insideof the boss portion 124 c. The intermediate portion 184 has an innerdiameter slightly larger than the outer diameter of the central axisportion 181. The shaft seal 124 e is placed at an outside of theintermediate portion 184.

The small diameter portion 185 forms a space in which the compressionspring 26 described later is placed. The small diameter portion 185 hasthe inner diameter which is slightly larger than the inner diameter ofthe intermediate portion 184. A connecting end surface 185 a, whichconnects between the intermediate portion 184 and the small diameterportion 185, is a contact portion to which one end portion of thecompression spring 26 contacts. The large diameter portion 186 isconnected to an outside of the small diameter portion 185.

The large diameter portion 186 is located on an outer side of the smalldiameter portion 185 in the radial direction DRr. The large diameterportion 186 has the inner diameter that is slightly larger than theinner diameter of the small diameter portion 185. The large diameterportion 186 has a body portion 186 a shaped in a tubular form, a firstlarge diameter anchoring portion 186 b, a second large diameteranchoring portion 186 c and a flange portion 186 d.

The first large diameter anchoring portion 186 b is a hook anchoringportion to which a hook 282 of the first torsion spring 28 is anchored.As shown in FIGS. 8 and 9, the first large diameter anchoring portion186 b is formed at an outside of the body portion 186 a at one axialside of the body portion 186 a, which is located on the one side in theaxial direction DRa. The first large diameter anchoring portion 186 boutwardly projects from the body portion 186 a in the radial directionDRr such that the first large diameter anchoring portion 186 b isopposed to the hook 282 of the first torsion spring 28 in thecircumferential direction DRc.

The second large diameter anchoring portion 186 c is a hook anchoringportion to which a hook 301 of the second torsion spring 30 is anchored.As shown in FIGS. 8 and 9 , the second large diameter anchoring portion186 c is formed at the outside of the body portion 186 a on the otherside of the first large diameter anchoring portion 186 b which islocated on the other side in the axial direction DRa. The second largediameter anchoring portion 186 c outwardly projects from the bodyportion 186 a in the radial direction DRr such that the second largediameter anchoring portion 186 c is opposed to the hook 301 of thesecond torsion spring 30 in the circumferential direction DRc.

The flange portion 186 d is an anchoring piece through which the shaft18 engages with an engaging portion of a lever 24 described later. Asshown in FIGS. 8 and 9 , the flange portion 186 d is formed at theoutside of the body portion 186 a on the other side of the second largediameter anchoring portion 186 c in the axial direction DRa. The flangeportion 186 d outwardly projects from the body portion 186 a in theradial direction DRr such that the flange portion 186 d is opposed tothe engaging portion of the lever 24 in the circumferential directionDRc.

The holder portion 182, which is formed in the above-described manner,receives the urging force of the first torsion spring 28 and the urgingforce of the second torsion spring 30 by having the first large diameteranchoring portion 186 b and the second large diameter anchoring portion186 c.

The rotor 20 is rotated about the central axis CL of the shaft 18 by theoutput of the drive device 16. The rotor 20 increases or decreases theopening degree of each of the flow passage holes 141, 142 of thestationary disk 14 in response to the rotation of the shaft 18. As shownin FIGS. 11, 12, 13 and 14 , the rotor 20 includes: the drive disk 22,which serves as a valve element; and the lever 24 which couples thedrive disk 22 to the shaft 18.

As shown in FIGS. 15, 16, 17 and 18 , the drive disk 22 is the valveelement that increases or decreases the opening degree of the first flowpassage hole 141 and the opening degree of the second flow passage hole142 in response to the rotation of the shaft 18. The opening degree ofthe first flow passage hole 141 is a degree of opening of the first flowpassage hole 141. Here, the opening degree of the first flow passagehole 141 in a full-opening state of the first flow passage hole 141 isindicated as 100%, and the opening degree of the first flow passage hole141 in a full-closing state of the first flow passage hole 141 isindicated as 0%. The full opening state of the first flow passage hole141 is, for example, a state where the first flow passage hole 141 isnot closed by the drive disk 22 at all. The full closing state of thefirst flow passage hole 141 is, for example, a state where the firstflow passage hole 141 is entirely closed by the drive disk 22. Thedefinition of the opening degree of the second flow passage hole 142 isthe same as the definition of the opening degree of the first flowpassage hole 141 described above.

The drive disk 22 is a circular disk member while a thickness directionof the drive disk 22 coincides with the axial direction DRa. The drivedisk 22 is placed in the inlet-side space 12 d such that the drive disk22 is opposed to the stationary disk 14 in the axial direction DRa. Thedrive disk 22 has the sliding surface 220 that is opposed to the openingsurface 140 of the stationary disk 14. The sliding surface 220 is a sealsurface that seals the opening surface 140 of the stationary disk 14.

It is desirable that the drive disk 22 is made of a material that has asmaller linear expansion coefficient and superior wear resistance thanthe material of the housing 12. The material of the drive disk 22 is ahigh-hardness material that is harder than the material of the housing12. Specifically, the drive disk 22 is made of ceramic. Alternatively,the drive disk 22 may be formed such that only a portion of the drivedisk 22, which forms the sliding surface 220, is made of the material,such as the ceramic, which has the smaller linear expansion coefficientand the superior wear resistance than the material of the housing 12.

The ceramic is a material that has: a small linear expansioncoefficient; a small dimensional change upon absorption of water; andexcellent wear resistance. When the drive disk 22 is made of theceramic, a relative positional relationship between the drive disk 22and the shaft 18 and a relative positional relationship between thedrive disk 22 and the housing 12 are stabilized. As a result, it ispossible to ensure the accuracy of the flow rate control of the fluidand limit unintended fluid leakage.

A rotor hole 221 is formed at the drive disk 22 at a location that isdisplaced from the central axis CL of the shaft 18. The rotor hole 221is a through-hole that extends through the drive disk 22 in the axialdirection DRa. The rotor hole 221 is formed at a portion of the drivedisk 22 where the rotor hole 221 can overlap with the first flow passagehole 141 and the second flow passage hole 142 in the axial direction DRawhen the drive disk 22 is rotated about central axis CL of the shaft 18.

A shaft insertion hole 223, through which the shaft 18 is inserted, isformed generally at a center of the drive disk 22. The shaft insertionhole 223 has an inner diameter that is larger than the diameter of theshaft 18 so as to limit sliding of the shaft 18 along the shaftinsertion hole 223.

In the valve device 10, when the drive disk 22 is rotated such that therotor hole 221 overlaps with the first flow passage hole 141 in theaxial direction DRa, the first flow passage hole 141 is opened.Furthermore, in the valve device 10, when the drive disk 22 is rotatedsuch that the rotor hole 221 overlaps with the second flow passage hole142 in the axial direction DRa, the second flow passage hole 142 isopened.

The drive disk 22 is configured to adjust a flow rate ratio between aflow rate of the fluid, which passes through the first flow passage hole141, and a flow rate of the fluid, which passes through the second flowpassage hole 142. That is, the drive disk 22 is configured to decreasethe opening degree of the second flow passage hole 142 in response to anincrease in the opening degree of the first flow passage hole 141.

The lever 24 is a coupling member that couples the drive disk 22 to theshaft 18. The lever 24 is fixed to the drive disk 22 and couples betweenthe drive disk 22 and the shaft 18 to enable integral rotation of thedrive disk 22 and the shaft 18 in a state where the drive disk 22 isdisplaceable in the axial direction DRa of the shaft 18.

Specifically, as shown in FIGS. 19, 20, 21 and 22 , the lever 24includes a circular disk portion 241, a first arm portion 242 and asecond arm portion 243. The circular disk portion 241, the first armportion 242 and the second arm portion 243 are formed integrally inone-piece as an integral molded product.

An intermediate insertion hole 241 a, through which the shaft 18 isinserted, is formed generally at a center of the circular disk portion241. The circular disk portion 241 is sized such that the circular diskportion 241 does not overlap with the shaft insertion hole 223 in theaxial direction DRa. The first arm portion 242 and the second armportion 243 are joined to the circular disk portion 241.

Each of the first arm portion 242 and the second arm portion 243outwardly projects from the circular disk portion 241 in the radialdirection DRr. The first arm portion 242 and the second arm portion 243project in opposite directions, respectively.

Specifically, the first arm portion 242 has a first engaging claw 242 aand a second engaging claw 242 b which project in the axial directionDRa from a side of the first arm portion 242 that is opposite to anopposing surface of the first arm portion 242 opposed to the drive disk22. Each of the first engaging claw 242 a and the second engaging claw242 b is shaped in an L-shape. A root side of each of the first engagingclaw 242 a and the second engaging claw 242 b extends in the axialdirection DRa, and a distal end side of each of the first engaging claw242 a and the second engaging claw 242 b projects in the circumferentialdirection DRc. The distal end side of the first engaging claw 242 a andthe distal end side of the second engaging claw 242 b project inopposite directions, which are away from each other.

The first engaging claw 242 a is configured to engage with the flangeportion 186 d of the shaft 18. That is, the first engaging claw 242 a isthe engaging portion of the lever 24 that is configured to engage withthe shaft 18. The first engaging claw 242 a has a portion that isopposed to the flange portion 186 d in the axial direction DRa and thecircumferential direction DRc.

Here, as shown in FIGS. 8 and 9 , the first engaging claw 242 a engageswith the flange portion 186 d in a state where a gap is formed betweenthe first engaging claw 242 a and the flange portion 186 d in the axialdirection DRa. Thereby, the lever 24 and the drive disk 22 are coupledto the shaft 18 in a state where the lever 24 and the drive disk 22 aredisplaceable in the axial direction DRa.

The second engaging claw 242 b is a hook anchoring portion to which ahook 302 of the second torsion spring 30 is anchored. When the hook 302of the second torsion spring 30 is anchored to the second engaging claw242 b, an urging force of the second torsion spring 30 is applied to thelever 24. As a result, the contact state, in which the first engagingclaw 242 a and the flange portion 186 d contact with each other, ismaintained by the urging force of the second torsion spring 30. Thefirst engaging claw 242 a is a contact portion that is configured tocontact the shaft 18.

A first protrusion 242 c is formed at an opposing surface of the firstarm portion 242 which is opposed to the drive disk 22. The firstprotrusion 242 c protrudes toward the drive disk 22 such that the firstprotrusion 242 c can be press-fitted into a first press-fitting groove224 formed at the drive disk 22. The first protrusion 242 c has a firstslit 242 d that extends through a center portion of the first protrusion242 c from a front side to a back side thereof. A degree of freedom ofdeformation of the first protrusion 242 c at the time of press-fittingthe first protrusion 242 c into the first press-fitting groove 224 isincreased by forming the first slit 242 d at the first protrusion 242 c.

The second arm portion 243 has a third engaging claw 243 a and a fourthengaging claw 243 b which project in the axial direction DRa from a sideof the second arm portion 243 that is opposite to an opposing surface ofthe second arm portion 243 opposed to the drive disk 22. The thirdengaging claw 243 a and the fourth engaging claw 243 b are configuredsubstantially the same manner as that of the first engaging claw 242 aand the second engaging claw 242 b.

A second protrusion 243 c is formed at an opposing surface of the secondarm portion 243 which is opposed to the drive disk 22. The secondprotrusion 243 c protrudes toward the drive disk 22 such that the secondprotrusion 243 c can be press-fitted into a second press-fitting groove225 formed at the drive disk 22. The second protrusion 243 c has asecond slit 243 d that extends through a center portion of the secondprotrusion 243 c from a front side to a back side thereof. A degree offreedom of deformation of the second protrusion 243 c at the time ofpress-fitting the second protrusion 243 c into the second press-fittinggroove 225 is increased by forming the second slit 243 d at the secondprotrusion 243 c.

The lever 24, which is configured in the above-described manner, isfixed to the drive disk 22 by press-fitting the protrusions 242 c, 243 cinto the press-fitting grooves 224, 225, respectively. In the lever 24of the present embodiment, the first arm portion 242 and the second armportion 243 have substantially the identical shape so as to bepoint-symmetric to each other with respect to the intermediate insertionhole 241 a. As a result, even in a state where the lever 24 is rotatedby 180° in the circumferential direction DRc, the lever 24 can beassembled to the shaft 18 and the drive disk 22.

As shown in FIGS. 3 and 10 , the compression spring 26 is a spring thaturges the rotor 20 against the stationary disk 14. The compressionspring 26 is a resilient member which is resiliently deformable in theaxial direction DRa of the shaft 18. The compression spring 26 is placedat the inside of the housing 12 in a state where the compression spring26 is compressed in the axial direction DRa. The one end portion of thecompression spring 26, which faces the one side in the axial directionDRa, contacts the shaft 18, and the other end portion of the compressionspring 26, which faces the other side in the axial direction DRa,contacts the rotor 20. More specifically, the one end portion of thecompression spring 26, which faces the one side in the axial directionDRa, contacts the connecting end surface 185 a of the inside of theholder portion 182, and the other end portion of the compression spring26, which faces the other side in the axial direction DRa, contacts thecircular disk portion 241. The compression spring 26 is not fixed to atleast one of the rotor 20 and the shaft 18, so that the compressionspring 26 does not function as a torsion spring.

The compression spring 26 urges the rotor 20 against the stationary disk14, so that a contact state, in which the opening surface 140 of thestationary disk 14 and the sliding surface 220 of the drive disk 22contact with each other, is maintained. This contact state is a state inwhich the opening surface 140 of the stationary disk 14 and the slidingsurface 220 of the drive disk 22 make a surface-to-surface contact witheach other. That is, the valve device 10 can maintain a posture of thedrive disk 22 such that the drive disk 22 is in contact with thestationary disk 14.

Specifically, the compression spring 26 is arranged to surround thecentral axis CL of the shaft 18. In other words, the shaft 18 is placedat the inside of the compression spring 26. With this configuration, aload of the compression spring 26 on the drive disk 22 is restrainedfrom being locally increased in the circumferential direction DRc of theshaft 18, so that the contact state between the sliding surface 220 andthe opening surface 140 can be easily maintained.

The first torsion spring 28 is a spring that urges the shaft 18 relativeto the housing 12 in the circumferential direction DRc around thecentral axis CL of the shaft 18. The first torsion spring 28 is placedbetween the housing 12 and the shaft 18.

Specifically, the first torsion spring 28 has two hooks 281, 282 whichare located at two opposite ends, respectively, of the first torsionspring 28 in the axial direction DRa and outwardly project in the radialdirection DRr. For convenience of explanation, hereinafter, the hook281, which is located on the one side in the axial direction DRa, willbe referred to as a first hook 281, and the hook 282, which is locatedon the other side in the axial direction DRa, will be referred to as asecond hook 282.

As shown in FIGS. 23 and 24 , the second hook 282 is anchored to thefirst large diameter anchoring portion 186 b of the holder portion 182.Since the second hook 282 is anchored to the first large diameteranchoring portion 186 b, which is a rotatable member, a position of thesecond hook 282 changes in the circumferential direction DRc when therotor 20 is rotated.

As shown in FIGS. 24 and 25 , the first hook 281 is anchored to a mainbody-side anchoring portion 124 h of the main body cover 124. The mainbody-side anchoring portion 124 h is formed by a protrusion that isformed at the inside of the rib portion 124 b. Since the first hook 281is anchored to the main body cover 124, which is a non-rotatable member,a position of the first hook 281 does not change even when the rotor 20is rotated.

The first torsion spring 28 is basically used in a state where the firsttorsion spring 28 is twisted and resiliently deformed in thecircumferential direction DRc. The urging force of the first torsionspring 28 is exerted to the shaft 18 at the time of rotating the shaft18 and at the time of stopping the rotation of the shaft 18. The urgingforce of the first torsion spring 28 is transmitted as a rotationalforce from the gear arrangement of the drive device 16 to the electricmotor through the shaft 18. Therefore, by placing the first torsionspring 28 between the housing 12 and the shaft 18, rattling in thecircumferential direction DRc between the drive device 16 and the shaft18 is limited. Note that the first torsion spring 28 is only twisted inthe circumferential direction DRc and is not compressed in the axialdirection DRa.

Here, a movable range of the shaft 18 in the circumferential directionDRc will be described with reference to FIG. 26 . The movable range ofthe shaft 18 is a rotation range within which the shaft 18 can berotated around the central axis CL.

As shown in FIG. 26 , the movable range of the shaft 18 includes: anurging range, in which the first torsion spring 28 urges the shaft 18 inthe circumferential direction DRc; and a non-urging range, in which thefirst torsion spring 28 does not urge the shaft 18 in thecircumferential direction DRc. The urging range is a rotation range inwhich the second hook 282 is in contact with the first large diameteranchoring portion 186 b, and thereby the urging force of the firsttorsion spring 28 is exerted to the shaft 18. Furthermore, thenon-urging range is a rotation range in which the second hook 282 isspaced away from the first large diameter anchoring portion 186 b, andthereby the urging force of the first torsion spring 28 is not exertedto the shaft 18. The reference position is a rotation range in which theurging force of the first torsion spring 28 applied to the shaft 18 isminimized in the state where the second hook 282 is in contact with thefirst large diameter anchoring portion 186 b.

The second torsion spring 30 is a spring that urges the lever 24relative to the shaft 18 in the circumferential direction DRc. Thesecond torsion spring 30 is placed between the shaft 18 and the lever24. A dimension of the second torsion spring 30 in the axial directionDRa and a dimension of the second torsion spring 30 in the radialdirection DRr are smaller than those of the first torsion spring 28.

The second torsion spring 30 has the two hooks 301, 302 which arelocated at two opposite ends, respectively, of the second torsion spring30 in the axial direction DRa and outwardly project in the radialdirection DRr. For convenience of explanation, hereinafter, the hook301, which is located on the one side in the axial direction DRa, willbe referred to as a third hook 301, and the hook 302, which is locatedon the other side in the axial direction DRa, will be referred to as afourth hook 302.

As shown in FIGS. 8 and 9 , the third hook 301 of the second torsionspring 30 is anchored to the second large diameter anchoring portion 186c of the holder portion 182. Furthermore, as shown in FIG. 7 , thefourth hook 302 is anchored to the second engaging claw 242 b of thelever 24.

The second torsion spring 30 is basically used in a state where thesecond torsion spring 30 is twisted and resiliently deformed in thecircumferential direction DRc. The urging force of the second torsionspring 30 is exerted to the lever 24 at the time of rotating the shaft18 and at the time of stopping the rotation of the shaft 18. The urgingforce of the second torsion spring 30 is transmitted as a rotationalforce to the drive disk 22 through the lever 24. Therefore, by placingthe second torsion spring 30 between the shaft 18 and the lever 24,rattling in the circumferential direction DRc between the shaft 18 andthe lever 24 is limited. Since the lever 24 is fixed to the drive disk22, the second torsion spring 30 limits rattling in the circumferentialdirection DRc in the transmission path that is from the shaft 18 to thedrive disk 22. Note that the second torsion spring 30 is only twisted inthe circumferential direction DRc and is not compressed in the axialdirection DRa.

In the valve device 10, by engaging the flange portion 186 d of theshaft 18 with the first engaging claw 242 a of the lever 24 in the statewhere the second torsion spring 30 is interposed between the shaft 18and the lever 24, these three components are assembled together as asub-assembly.

Next, an operation of the valve device 10 of the present embodiment willbe described. In the valve device 10, as shown in FIGS. 1, 2 and 3 , thefluid flows from the inlet port 12 a into the inlet-side space 12 d, asindicated by an arrow Fi. In a case where the first flow passage hole141 is opened, the fluid flows from the inlet-side space 12 d into thefirst outlet-side space through the first flow passage hole 141. Thefluid, which is supplied into the first outlet-side space, flows fromthe first outlet-side space to the outside of the valve device 10through the first outlet port 12 b, as indicated by an arrow F1 o. Inthis case, the flow rate of the fluid, which passes through the firstflow passage hole 141, is determined according to the opening degree ofthe first flow passage hole 141. That is, the flow rate of the fluid,which flows from the inlet port 12 a to the first outlet port 12 bthrough the first flow passage hole 141, is increased when the openingdegree of the first flow passage hole 141 is increased.

In a case where the second flow passage hole 142 is opened, the fluidflows from the inlet-side space 12 d into the second outlet-side spacethrough the second flow passage hole 142. The fluid, which is suppliedinto the second outlet-side space, flows from the second outlet-sidespace to the outside of the valve device 10 through the second outletport 12 c, as indicated by an arrow F2 o. In this case, the flow rate ofthe fluid, which passes through the second flow passage hole 142, isdetermined according to the opening degree of the second flow passagehole 142. That is, the flow rate of the fluid, which flows from theinlet port 12 a to the second outlet port 12 c through the second flowpassage hole 142, is increased when the opening degree of the secondflow passage hole 142 is increased.

The valve device 10 described above can provide, for example, thefollowing advantages.

(1) The rotor 20 of the valve device 10 includes: the drive disk 22; andthe lever 24 that is fixed to the drive disk 22 and couples between thedrive disk 22 and the shaft 18 to enable integral rotation of the drivedisk 22 and the shaft 18 in the state where the drive disk 22 isdisplaceable in the axial direction DRa of the shaft 18. In the valvedevice 10, the first torsion spring 28 is placed between the housing 12and the shaft 18, and the second torsion spring 30 is placed between theshaft 18 and the lever 24.

Therefore, as long as the first torsion spring 28 urges the shaft 18relative to the housing 12 in the circumferential direction DRc, therattling in the circumferential direction DRc between the drive device16 and the shaft 18 is limited. In addition, as long as the secondtorsion spring 30 urges the lever 24 relative to the shaft 18 in thecircumferential direction DRc, the rattling in the circumferentialdirection DRc between the shaft 18 and the lever 24 is limited. Sincethe lever 24 is fixed to the drive disk 22, the second torsion spring 30limits the rattling in the circumferential direction DRc between theshaft 18 and the drive disk 22.

Therefore, the rattling in the circumferential direction DRc in thetransmission path from the drive device 16 to the rotor 20 can belimited, and thereby the variations in the opening degrees of the flowpassage holes 141, 142 caused by the rattling can be limited.

In addition, the drive disk 22 is coupled to the shaft 18 in the statewhere the drive disk 22 is displaceable in the axial direction DRa.Therefore, even when the second torsion spring 30 is placed between theshaft 18 and the lever 24, the surface-to-surface contact between thesliding surface 220 of the drive disk 22 and the stationary disk 14 canbe maintained satisfactorily.

Here, in the case where a single torsion spring is used to limit therattling in the circumferential direction DRc in the transmission pathfrom the drive device 16 to the rotor 20, the urging force of thetorsion spring becomes excessively large, and thereby an increase in theload on the drive device 16 is unavoidable.

In contrast, the valve device 10 of the present embodiment is configuredto limit the rattling in the circumferential direction DRc in thetransmission path from the drive device 16 to the rotor 20 by the firsttorsion spring 28 and the second torsion spring 30. With thisconfiguration, the urging force of the respective torsion springs 28, 30is limited, and thereby the increase in the load on the drive device 16can be limited.

(2) The shaft 18 includes: the central axis portion 181 that is made ofthe metal and includes the central axis CL while the central axisportion 181 extends in the axial direction DRa; and the holder portion182 that is made of the resin and is coupled to the central axis portion181. The holder portion 182 is configured to receive the urging force ofthe first torsion spring 28 and the urging force of the second torsionspring 30.

According to this structure, the rigidity and accuracy (that is,straightness) of the shaft 18 can be ensured as compared with the casewhere the entire shaft 18 is made of a resin material. Moreover, whenthe holder portion 182 is made of the resin, it is possible to realizethe shaft 18 that is lightweight and has a complex shape. In particular,by ensuring the straightness of the shaft 18, a clearance of, forexample, the bearing 124 g can be reduced. Therefore, a positionaldeviation of the shaft 18 in the radial direction can be limited.

(3) The shaft 18 extends through the stationary disk 14 and the drivedisk 22 and is rotatably supported by the housing 12.

By adopting the structure in which the shaft 18 extends through thestationary disk 14 and the drive disk 22, the stationary disk 14 and thedrive disk 22 can be centered by the shaft 18. As a result, thepositional deviation of the stationary disk 14 and the drive disk 22 inthe radial direction (that is, the radial direction DRr) can be limited.This is effective for limiting the variations in the opening degree ofthe respective flow passage holes 141, 142.

(4) The housing 12 has the mounting portion 122 a that contacts the backsurface of the stationary disk 14 which is opposite to the openingsurface 140 of the stationary disk 14 placed in contact with the slidingsurface 220. The gasket 15 is placed between the stationary disk 14 andthe mounting portion 122 a and is configured to seal the gap between thestationary disk 14 and the mounting portion 122 a. According to this,leakage of the fluid from the gap between the stationary disk 14 and themounting portion 122 a can be limited.

(5) The valve device 10 includes the compression spring 26 that isconfigured to urge the rotor 20 against the stationary disk 14. The twoor more protrusions 152 are formed at the seal surface of the gasket 15.

As described above, when the projections 152 are formed at the sealsurface of the gasket 15, the urging force of the compression spring 26can be reduced in comparison to the case where the seal surface is flat,and thereby the sliding resistance, which is generated between the drivedisk 22 and the stationary disk 14, can be reduced. Moreover, when thetwo or more projections 152 are provided at the seal surface of thegasket 15, the posture of the gasket 15 is more stable in comparison toa case where a single projection is provided on the seal surface.Therefore, the sealing performance of the gasket 15 can be ensured.

(6) The movable range of the shaft 18 in the circumferential directionincludes: the urging range in which the first torsion spring 28 urgesthe shaft 18 in the circumferential direction DRc; and the non-urgingrange in which the first torsion spring 28 does not urge the shaft 18 inthe circumferential direction DRc.

According to this, for example, at the time of assembling the firsttorsion spring 28 to the housing 12 and the shaft 18, it is notnecessary to assemble the first torsion spring 28 in the twisted stateby setting the rotational position of the shaft 18 to the non-urgingrange. By rotating the shaft 18 to some extent after assembling thefirst torsion spring 28, the torsional resilient deformation of thefirst torsion spring 28 can be obtained.

(7) The lever 24 has the first engaging claw 242 a (serving as theengaging portion) that is configured to engage with the shaft 18 in thestate where the second torsion spring 30 is interposed between the lever24 and the shaft 18.

According to this, the three components, i.e., the lever 24, the secondtorsion spring 30 and the shaft 18 can be assembled together as thesub-assembly by engaging the first engaging claw 242 a of the lever 24with the shaft 18 in the state where the second torsion spring 30 isinterposed between the lever 24 and the shaft 18. This greatlycontributes to the improvement of the assemblability of the valve device10.

OTHER EMBODIMENTS

Although the representative embodiment of the present disclosure hasbeen described above, the present disclosure is not limited to theabove-described embodiment and can be variously modified, for example,as follows.

Although the components of the valve device 10 have been described indetail in the above embodiment, the components are not limited to thosedescribed above and may differ from those described above.

As described in the above embodiment, it is desirable that the shaft 18includes the central axis portion 181 made of the metal and the holderportion 182 made of the resin. However, the present disclosure is notlimited to this. For example, the shaft 18 may be formed such that thecentral axis portion 181 and the holder portion 182 are made of one ofthe metal material and the resin material.

In the above-described embodiment, there is exemplified that the two endportions of the shaft 18 are rotatably supported by the housing 12.However, the valve device 10 is not limited to this. In the valve device10, for example, one end portion of the shaft 18 may be rotatablysupported by the stationary disk 14. Furthermore, in the valve device10, for example, only one of the two end portions of the shaft 18 may berotatably supported by the housing 12.

In the above-described embodiment, the compression spring 26 urges therotor 20 against the stationary disk 14. However, the valve device 10 ofthe present disclosure is not limited to this configuration. The valvedevice 10 may be configured such that, for example, an elastomer, whichis shaped in a cylindrical tubular form and is resiliently deformable inthe axial direction DRa of the shaft 18, may be used to urge the rotor20 against the stationary disk 14. Furthermore, the valve device 10 maybe configured such that a pressure difference between the inlet-sidespace 12 d and the outlet-side space 12 e is used to urge the rotor 20against the stationary disk 14. As indicated above, the compressionspring 26 is not an essential component in the valve device 10.

As described in the above embodiment, it is desirable that the gasket 15has the two projections 151, 152 at each of the seal surfaces of thegasket 15. However, the present disclosure is not limited to this. Forexample, one projection or three or more projections may be formed ateach of the seal surfaces of the gasket 15. Moreover, each of the sealsurfaces of the gasket 15 may be a flat surface. It should be noted thatthe gasket 15 is not essential in the valve device 10 and may beeliminated.

As described in the above embodiment, it is desirable that in the valvedevice 10, the movable range of the shaft 18 includes the non-urgingrange. However, the present disclosure is not limited to this. In thevalve device 10, the movable range of the shaft 18 does not have toinclude the non-urging range.

As described in the above embodiment, it is desirable that in the valvedevice 10, the lever 24 includes the engaging portion which isconfigured to engage with the shaft 18 in the state where the secondtorsion spring 30 is interposed between the lever 24 and the shaft 18.However, this engaging portion may be eliminated.

In the above-described embodiment, there is exemplified that the valvedevice 10 is formed as the three-way valve. However, the valve device 10is not limited to the three-way valve. The valve device 10 of thepresent disclosure may be configured as, for example, a flow rateadjusting valve or an on-off valve which has one fluid inlet and onefluid outlet. In this case, one flow passage hole is formed at thestationary disk 14. The valve device 10 of the present disclosure maybe, for example: a multi-way valve having one fluid inlet and three ormore fluid outlets; a multi-way valve having three or more fluid inletsand one fluid outlet; or a multi-way valve having a plurality of fluidinlets and a plurality of fluid outlets.

In the above-described embodiment, there is described the example wherethe valve device 10 of the present disclosure is applied as the controlvalve for the vehicle. However, the valve device 10 of the presentdisclosure may be applied as a control valve for other machines that isother than the vehicle.

Needless to say, in the above-described embodiments, the components ofthe embodiment(s) are not necessarily essential except when it isclearly indicated that they are essential and when they are clearlyconsidered to be essential in principle.

In the above-described embodiments, when the numerical values, such asthe number, numerical value, quantity, range, etc. of the components ofthe embodiment(s) are mentioned, the numerical values are not limited tothose described in the embodiment(s) except when it is clearly indicatedthat the numeric values are essential and when the numeric values areclearly considered to be essential in principle.

In the above-described embodiments, when a shape, a positionalrelationship, etc. of the component(s) is mentioned, the shape,positional relationship, etc. are not limited to those described in theembodiment(s) unless otherwise specified or limited in principle to thethose described in the embodiment(s).

What is claimed is:
 1. A valve device comprising: a housing that forms afluid passage at an inside of the housing, wherein the fluid passage isconfigured to conduct fluid through the housing; a stationary disk thatis shaped in a plate form and is fixed at the inside of the housing,wherein the stationary disk has at least one flow passage hole which isconfigured to conduct the fluid through the stationary disk; a drivedevice that is configured to output a rotational force; a shaft that isconfigured to be rotated about a central axis, which is predetermined,by the rotational force; and a rotor that is configured to increase ordecrease an opening degree of the at least one flow passage hole inresponse to rotation of the shaft, wherein: the rotor includes: a drivedisk that is shaped in a plate form and is configured to slide relativeto the stationary disk; and a lever that is fixed to the drive disk andcouples between the drive disk and the shaft to enable integral rotationof the drive disk and the shaft in a state where the drive disk isdisplaceable in an axial direction of the shaft; a first torsion springis placed between the housing and the shaft and is configured to urgethe shaft relative to the housing in a circumferential direction aroundthe central axis of the shaft; and a second torsion spring is placedbetween the shaft and the lever and is configured to urge the leverrelative to the shaft in the circumferential direction.
 2. The valvedevice according to claim 1, wherein the shaft includes: a central axisportion that is made of metal and includes the central axis while thecentral axis portion extends in the axial direction; and a holderportion that is made of resin and is coupled to the central axisportion, wherein the holder portion is configured to receive an urgingforce of the first torsion spring and an urging force of the secondtorsion spring.
 3. The valve device according to claim 1, wherein theshaft extends through the stationary disk and the drive disk and isrotatably supported by the housing.
 4. The valve device according toclaim 1, wherein: the drive disk has a sliding surface that is opposedto the stationary disk; the housing has a mounting portion that contactsa back surface of the stationary disk which is opposite to a contactsurface of the stationary disk placed in contact with the slidingsurface; and a gasket is placed between the stationary disk and themounting portion and is configured to seal a gap between the stationarydisk and the mounting portion.
 5. The valve device according to claim 4,comprising a compression spring that is configured to urge the rotoragainst the stationary disk, wherein two or more projections are formedat a seal surface of the gasket.
 6. The valve device according to claim1, wherein a movable range of the shaft in the circumferential directionincludes: an urging range in which the first torsion spring urges theshaft in the circumferential direction; and a non-urging range in whichthe first torsion spring does not urge the shaft in the circumferentialdirection.
 7. The valve device according to claim 1, wherein the leverhas an engaging portion that is configured to engage with the shaft in astate where the second torsion spring is interposed between the leverand the shaft.